A 24 hour bath in an 8 dollar crock pot with 1/2gal of green anti-freeze on Low will remove anything found on our motors, aluminum or otherwise, and leave the aluminum factory fresh without any metal removal or scrubbing. The aluminum will be as bright as it was cast.
Just remove the backplate and head. Leave the piston, crank and rod in. Add all the parts to the bath. Small parts such as screws or such can go into a small sieve basket with handle removed. Remove all the parts with a kitchen tong after it all cools down, or turkey baister the fluid back into the jug.
After cooking, you can remove the sleeve no problem and usually pop the bearings all in one stroke while everything is still hot.
Keep this out in the shed, do not breath fumes, do not re-use the crock pot or anything else used in this process for food ever again. Destroy the clay pot before putting into trash if trashed.
You can clean entire motors this way excluding anything plastic or rubber. In other words, remove the carb and clean that seperate - all that can go into Hoppe's No. 9 Gun Cleaning Fluid for 2 or 3 hours. Makes brass new again - dissolves all sludge. Rinse with soap and water.
The entire process will involve almost no brushing. If brushing is needed, use a stainless steel welding brush with Wrights Copper Cleaner (grocery store item) or use it with an old toothbrush. All water based and rinses clean as a whistle.
Bottle brushes are nice for using the cream inside the crankshaft bore. Gun brushes work good for the carb hole. Gum brushes found near the toothbrushes work good for tapped holes and needle valve assemblies.
Always wash every part with soap and water and a rag, and also dry with a rag. The dry rag will show you anything that needs more cleaning if you see any deposits in the rag.
Use a hot water rinse for less water spotting, or keep the oven warm with a cookie sheet to place parts on as you go. Spray your steel parts with WD-40 after rinsing. Don't wait for these to air dry...they will have no oil on them and will rust as they dry.
Works like magic. After this process you can start your rebuilding with basically parts that are as clean as the day they were born...
I go one more step and heat my steel parts (screws or couplers) in a pot of boiling water with a few birthday candles thrown in to cover the top of the water, and remove the parts with tongs - or wire hang them first. This hot waxes all your steel nice and thin when removed from the pot and stops screws from rusting inside the tapped holes after assembly, and keeps your coupler threads in good shape also.
